已知5个水果商店苹果的单价和销售额,要求计算5个商店苹果的平均单价,应该采用()。
A.简单算术平均法
B.加权算术平均法
C.加权调和平均法
D.几何平均法
参考答案:C
The overweight adolescent client tells the nurse that he would like to lose weight and asks the nurse’s opinion on how to accomplish his goal. Which of the following suggestions would be most appropriate
A. Exercising more often.B. Severely limiting calorie intake.C. Participating in an adolescent weight-reduction program.D. Cutting clown on sweets and other snacks.
三氯化磷分子的空间构型是三角锥形而不是平面正三角形,下列关于三氯化磷分子空间构型理由的叙述,不正确的是( )
A.PCl3分子中三个共价键的键长、键角都相等
B.PCl3分子中的P-Cl键属于极性共价键
C.PCl3分子中三个共价键键能、键角均相等
D.PCl3是非极性分子